IS-IS IPv6 Advertise Passive Only

The IS-IS IPv6 Advertise Passive Only feature allows you to configure the Intermediate System-to-Intermediate System (IS-IS) instance on a device to advertise only IPv6 prefixes that belong to passive interfaces and exclude other connected IPv6 prefixes.

Finding Feature Information

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Prerequisites for IS-IS IPv6 Advertise Passive Only

Before you can use the IS-IS IPv6 Advertise Passive Only feature to exclude IPv6 prefixes of connected networks from IS-IS link-state protocol (LSP) data unit advertisements, the integrated IS-IS routing protocol must be configured. See the “Configuring a Basic IS-IS Network” section of the IP Routing: ISIS Configuration Guide.

Information About IS-IS IPv6 Advertise Passive Only

IPv6 Prefixes Only Allowed on Passive Interfaces

You can configure the IS-IS instance on a device to allow only IPv6 prefixes that belong to passive interfaces in its LSP advertisements. This configuration reduces the number of IPv6 prefixes carried in the LSP advertisement.

How to Configure IS-IS IPv6 Advertise Passive Only

Configuring IS-IS Instances on a Device to Advertise Passive Interface IPv6 Prefixes Only

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    router isis [area-tag]

    4.    net net1

    5.    interface loopback number

    6.    ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}

    7.    exit

    8.    interface type number

    9.    ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}

    10.    ipv6 router isis [area-tag]

    11.    exit

    12.    router isis [area-tag]

    13.    passive-interface [default] type number

    14.    address-family ipv6

    15.    advertise passive-only

    16.    end


DETAILED STEPS
     Command or ActionPurpose
    Step 1 enable


    Example:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.

     
    Step 2 configure terminal


    Example:
    Device# configure terminal
     

    Enters global configuration mode.

     
    Step 3 router isis [area-tag]


    Example:
    Device(config)# router isis area1
     

    Configures an IS-IS routing process for IP on an interface, attaches an area designator to the routing process, and enters router configuration mode.

     
    Step 4net net1


    Example:
    Device(config-router)# net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
     

    Configures an IS-IS network entity table (NET) for the routing process.

     
    Step 5 interface loopback number


    Example:
    Device(config-router)# interface loopback 0
     

    Configures a loopback interface and enters interface configuration mode.

     
    Step 6 ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}


    Example:
    Device(config-if)# ipv6 address 2001:688:1001:1000::1/128
     

    Sets a primary IPv6 address for an interface.

     
    Step 7 exit


    Example:
    Device(config-if)# exit
     

    Returns to global configuration mode.

     
    Step 8 interface type number


    Example:
    Device(config)# interface FastEthernet 0/0
     

    Configures an interface type and enters interface configuration mode.

     
    Step 9 ipv6 address {ipv6-address/prefix-length | prefix-name sub-bits/prefix-length}


    Example:
    Device(config-if)# ipv6 address 2001:688:1001:100A::1/64
     

    Configures an IPv6 address for the interface.

     
    Step 10 ipv6 router isis [area-tag]


    Example:
    Device(config-if)# ipv6 router isis area1
     

    Configures an IS-IS routing process for IPv6 on an interface, attaches an area designator to the routing process, and enters router configuration mode.

     
    Step 11 exit


    Example:
    Device(config-if)# exit
     

    Returns to global configuration mode.

     
    Step 12 router isis [area-tag]


    Example:
    Device(config)# router isis area1
     

    Configures an IS-IS routing process for IP on an interface, attaches an area designator to the routing process, and enters router configuration mode.

     
    Step 13 passive-interface [default] type number


    Example:
    Device(config-router)# passive-interface loopback 0
     

    Disables sending routing updates on an interface.

     
    Step 14 address-family ipv6


    Example:
    Device(config-router)# address-family ipv6
     

    Enters address family configuration mode.

     
    Step 15 advertise passive-only


    Example:
    Device(config-router-af)# advertise passive-only
     

    Configures IS-IS to advertise only IPv6 prefixes that belong to passive interfaces.

     
    Step 16 end


    Example:
    Device(config-router-af)# end
     

    (Optional) Saves the configuration commands to the running configuration file and returns to privileged EXEC mode.

     

    Configuration Examples for IS-IS IPv6 Advertise Passive Only

    Example: Configuring IS-IS Instances on a Device to Advertise Only Passive Interfaces

    Device> enable
Device# configure terminal
Device(config)# router isis area1
Device(config-router)# net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
Device(config-router)# interface loopback 0
Device(config-if)# ipv6 address 2001:688:1001:1000::1/128
Device(config-if)# exit
Device(config)# interface Ethernet 0/0
Device(config-if)# ipv6 address 2001:688:1001:100A::1/64
Device(config-if)# ipv6 router isis area1
Device(config-if)# exit
Device(config)# router isis area1
Device(config-router)# passive-interface loopback 0
Device(config-router)# address-family ipv6
Device(config-router-af)# advertise passive-only

    Additional References

    Related Documents

    Related Topic

    Document Title

    IPv6 addressing and connectivity

    IPv6 Configuration Guide

    Cisco IOS commands

    Cisco IOS Master Commands List, All Releases

    IPv6 commands

    Cisco IOS IPv6 Command Reference

    Cisco IOS IPv6 features

    Cisco IOS IPv6 Feature Mapping

    IS-IS commands

    Cisco IOS IS-IS Command Reference

    Configuring the integrated IS-IS routing protocol

    “Configuring a Basic IS-IS Network” module of the IP Routing: ISIS Configuration Guide

    Standards and RFCs

    Standard/RFC

    Title

    RFCs for IPv6

    IPv6 RFCs

    MIBs

    MIB

    MIBs Link

    To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

    http:/​/​www.cisco.com/​go/​mibs

    Technical Assistance

    Description

    Link

    The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

    http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

    Feature Information for IS-IS IPv6 Advertise Passive Only

    The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

    Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.
    Table 1 Feature Information for IS-IS IPv6 Advertise Passive Only

    Feature Name

    Releases

    Feature Information

    IS-IS IPv6 Advertise Passive Only

    15.2(4)M

    Cisco IOS XE Release 3.6S

    Allows you to configure the IS-IS instance on a device to advertise only IPv6 prefixes that belong to passive interfaces and exclude other connected IPv6 prefixes.

    The following command was introduced or modified: advertise passive-only (IPv6).